As is known in the art, in tracking radars such as high frequency surface wave radar (HFSWR), performance is specified in terms of track range. Track ranges are greater for outbound targets than inbound targets. For inbound targets, track initiation is undertaken on signals having a low probability of detection (Pd). Consequently, track errors will also be greater. Frequency hopping, as being developed for next generation HFSWR, will compound the problem of track initiation for low probability of detection (Pd) signals.
As is also known, track retrodiction is a method applied to provide a more historical accurate estimate of a target's position. Track retrodiction techniques can be useful in track/motion forensic analysis particularly when associating data from multiple systems. Retrodiction techniques can be combined with track-to-track association to implement so-called “track stitching” which can be viewed as extending (or “stitching” a new track back into the past). Conventional retrodiction techniques do not associate detections prior to the initiation of the original track.
So-called “track-before-detect” techniques include those techniques in which a signal is tracked before declaring it a target. In such approaches, data about a tentative target are integrated over time and may yield detection in cases when signals from any particular time instance are too weak against clutter (low signal-to-noise ratio) to register a detected target.